The effects of selective lesions within the anterior thalamic nuclei on spatial memory in the rat

Behav Brain Res. 1996 Nov;81(1-2):189-98. doi: 10.1016/s0166-4328(96)89080-2.


Groups of rats received cytotoxic lesions centred in either the anterior thalamic nucleus (AM), the anterior ventral and anterior dorsal thalamic nuclei (AV/AD), or all three nuclei combined (ANT.T). These lesions were made by injecting N-methyl-D-aspartate acid (NMDA). These rats, and a group of surgical controls (SHAM), were trained on a rewarded forced-alternation task in a T-maze. While the selective AM and AV/AD lesions produced an initial acquisition impairment, only the animals with combined lesions (ANT.T) showed a persistent deficit throughout the 16 acquisition sessions. Subsequent testing with a cross-maze confirmed that the SHAM, AV/AD, and AM groups were able to use allocentric cues, while the ANT.T group were impaired. In contrast none of the three anterior groups were impaired on a subsequent egocentric discrimination and reversal task run in the same apparatus. A final test using the eight arm radial-maze, revealed marked deficits in the ANT.T group as well as milder deficits in the AV/AD group. The results from these experiments help to confirm the importance of the anterior thalamic nuclei for allocentric tasks, but suggest that no region is pre-eminently important. The findings also help to account for other studies which have reported that anterior thalamic lesions have seemingly mild effects on tests of spatial memory.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Discrimination Learning / physiology
  • Male
  • Mammillary Bodies / anatomy & histology
  • Mammillary Bodies / physiology
  • Maze Learning / physiology
  • Memory / physiology*
  • Motor Activity / physiology
  • Rats
  • Space Perception / physiology*
  • Thalamic Nuclei / anatomy & histology
  • Thalamic Nuclei / physiology*